Asbestos in vinyl floor tiles and lino

Vinyl with asbestos looks exactly like vinyl without it.

Do old vinyl floor tiles contain asbestos?

Possibly. asbestos.nsw.gov.au says asbestos-containing vinyl tiles and sheet flooring were made before 1987 and are likely still in many homes built before 1990 (asbestos.nsw.gov.au).

Is the backing the risky part?

Often. Some sheet vinyl has an asbestos-containing backing, which can be friable. Friable asbestos must be removed by a Class A licensed removalist (source).

Can I tile or lay floating floor over it?

Covering intact vinyl without sanding or lifting it disturbs less material than removal. Get it tested before any grinding, scraping or sanding.

How do I know for sure?

Only a lab test confirms it. A licensed assessor can take samples (how testing works).